Year	mm Hg
1980	132.9
1981	132.6
1982	132.3
1983	132
1984	131.7
1985	131.3
1986	131
1987	130.7
1988	130.5
1989	130.3
1990	130.2
1991	130.1
1992	130
1993	129.9
1994	129.8
1995	129.8
1996	129.8
1997	129.9
1998	130.1
1999	130.2
2000	130.4
2001	130.7
2002	131
2003	131.3
2004	131.6
2005	131.9
2006	132.2
2007	132.5
2008	132.8